The present invention relates generally to the electrical, electronic and computer arts, and, more particularly, to high-frequency detectors.
It has been demonstrated that high-frequency (e.g., terahertz (THz)) detectors based on p-n junction diodes provide certain benefits over diode-connected metal-oxide-semiconductor (MOS) transistors and heterojunction bipolar transistors (HBTs) due to their higher corner frequency, fc. Flicker noise, also referred to as 1/f noise, is often characterized by the corner frequency between the region dominated by the low-frequency flicker noise and the higher-frequency “flat-band” noise. MOS field-effect transistors (MOSFETs) typically exhibit a higher flicker noise and therefore a lower fc for a given flat-band noise, compared to junction field-effect transistors (JFETs) or bipolar transistors. The higher flicker noise in MOSFETs is often attributed to the presence of interface states between the gate dielectric and the channel of the transistor.
A higher fc allows the detector to achieve higher signal-to-noise ratio (SNR), which in turn provides a higher operation frequency. However, an upper limit of the operation frequency is still dictated, to a large extent, by an effective path length for carrier diffusion and an effective series resistance of the diode.